Process of making zinc formaldehyde hydrosulfite.



UNITED STATES HANS LABHARD T, OF MANNHEIM, GERMANY, ASSIGNOR TO BADISOHEAN-ILIN & SODA PATENT oEEroE F FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE,GERMANY, A CORPORATION.

PROCESS OF MAICING ZINC FORMALDEHYDE HYDROgULFITE.

are. 871,600.

To allwhomfit may concern:

Be it known that I, HANS LaBnAnnT, doctor of hilosophy and chemist,citizen of the Swiss fiepublic, residing at Mannheim, Germany, haveinvented new and useful Tmrovements: in Makin Zinc Formaldehydeydrosulfite, of which the following is a specification. r 1

In the specification of the application for Letters Patent Serial No.298,866 it is stated that by passing a current of gaseous sulfur dioxidinto a suspension of zinc dust in aqueous formaldehyde solution and,either by heating to a temperature of about 100 0., or by prolongedstirring at ordinary tem erature, a difficultl soluble zinc formalde ydesulfoxylate can e obtained.

I have now discovered that the reaction can be carried out so that aproduct is yielded which is an easily soluble zinc formaldehydehydrosulfite if the aforesaid com o- .nents be allowed to react on oneanot er while either cooling, or at ordinar temperature, or whileavoiding strongly eating, in

any case below fifty (50) de rees centigrade,

and the, reaction be stoppe( before the difli cultly s6luble zineformaldehyde sulfoxylate beginsto separate out. If the treatment beprolonged, less of the readily soluble salt and some of the diilicultly'soluble salt are obtained.

The following example will serve to illustratehow my nvention can beperformed,

but it is not confined to this example. The parts are by weight. Suspendt iree hundred and fifty-seven and a half (357.5) parts of zinc dustintwo thousand (2,000) parts of a fifteen (15) per cent. a ueousformaldehyde solution and, while ei l stirring, pass in a current ofsulfur dioxid until the increase in Weight is .about six hundred andforty (640) parts. The temperature is preferably maintained, by cooling,at about twenty (20) degrees centigrade, but in any case it shouldSpecification of Letters Patent.

Application filed Gc'tober 2. 1906- Sorial No. 337.104.

Patented Nov. 19, 1907.

. not exceed fift degrees centigrade. On

filtering oil t e residue of zinc dust and evaporating the filtrate in'vacuo zincffor maldehyde h drosulfiteis;obtained in the form of athici: syrup. The reaction can be re arded as taking place accordingto'the foilowing equation If the aqueous solution be treated with so-'mg to t e equation zns,o,2on,o Na 00 I Z1105), n sp zon o.

If the aforementioned aqueous solution of the zinc salt be boiled withzinc dust, basic maldeh (le hydrosulfite is obtained accord:

zinc formaldehyde sulfoxylate is obtained' according to the equation IZnS,O .2CH O Zn 2ZnSO,.OH O. The production of the easily soluble-zincformaldehyde hydrosulfite according ,to my' invention can be carried outin alcoholic instead of in aqueous'solution. Either dilute, or ordinarconcentrated spiritcan be employed. he temperature in this case alsomust not exceed fifty degrees centigrade.

N ow what I claim is:

The process of producing easily soluble zinc formaldehyde hydrosu te bycausing formaldehyde, zinc dust and sulfur dioxid to act on one anotherat a temperature below fift degrees centi rade.

l n testimony w ereof I have hereunto set my hand in the presence of twosubscribing witnesses.

- HANS LABHARDT.

Witnesses J. Anne. LLOYD, H. W. HARnIs.

